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(BEGIN VIDEOTAPE)

PIERS MORGAN, HOST: Tonight, dangers from the deep. Up close and person with some of the world's most terrifying predators: sharks.

JEFF CORWIN, HOST, "OCEAN MYSTERIES": The attack begins long before the bite happens.

MORGAN: Snakes.

CORWIN: This, my friend -- oh my goodness --

MORGAN: Oh my God.

CORWIN: -- is one of the largest snakes in captivity.

MORGAN: Wow.

CORWIN: I'd ask for help but I know I won't get it.

MORGAN: No, no, no.

Stingrays. And how is this for a set of teeth? Man-eating gators.

CORWIN: You came --

(CROSSTALK)

MORGAN: I'm not touching anything.

CORWIN: No?

MORGAN: You're in charge.

CORWIN: Jeff Corwin brings them all here.

MORGAN: How many people are keeping them --

CORWIN: A lot of people keep them as pets and they don't make good pets. They belong in the wild.

MORGAN: No kidding.

And I know what you're worried about -- will I survive? Find out in this PIERS MORGAN LIVE special, "Sharks and Reptiles."

(END VIDEOTAPE)

MORGAN: Good evening.

Regular viewers of this show will know I'm not afraid to talk to anybody or take on anything. Bring it on is what I always say. I can handle it.

Well, tonight, I'm not feeling quite so confident. We have some rather unusual guests in the studio, guests that scare the living daylights out of most people -- sharks, pythons, alligators, the stuff, frankly, of nightmares and also responsible for deadly attacks on humans.

But should they fear us more than we fear them?

Well, here with me now for the hour is Jeff Corwin. He's a wildlife biologist, TV presenter and host of ABC's big hit series, "Ocean Mysteries."

Jeff, welcome to you.

CORWIN: Thank you so much, Piers. I'm delighted.

MORGAN: My only experience with a shark was I was doing a little small dive in Barbados in the -- in Caribbean. And a hammerhead shark about 10 feet long just patrolled past us. And it was utterly terrifying. But that's my only experience.

But it gave me an insight into the ocean, these creatures, the power, the size and the terrifying nature.

Was I right to feel scared?

CORWIN: I think it's totally appropriate to be on guard, because they are incredibly predatory fish. And these are reasons why we react to sharks. I think it's in our genes.

But I think what you said earlier is so true. I think sharks, as a group of animals, have far more to fear from us than we do from them. But if I was in the water with a -- with a large hammerhead swimming about, I'd be a little unnerved.

But to me, what is amazing about these hammerhead sharks is what you're actually looking at is this incredible, exquisite design of evolution. Basically, that hammer of its head --

MORGAN: Yes?

CORWIN: -- is what it uses to pin down its target prey, which isn't a human being like us --

MORGAN: But do they attack humans?

CORWIN: -- it's the rays. MORGAN: Do hammerheads attack humans?

CORWIN: Rarely. It's very rare.

(CROSSTALK)

CORWIN: -- eat rays, stingrays.

MORGAN: Right.

What are the most predatory of all the sharks?

CORWIN: Well, there's a number of species that have been known to cross paths with people in a negative way. For example, we can see this arsenal of teeth right here. This is from a bull shark. And this is certainly (AUDIO GAP) amount of respect. Tiger sharks are another shark that we need to be careful about when -- when they're around us in the water.

But there are hundreds and hundreds --

MORGAN: -- and the great white.

CORWIN: -- of sharks.

The great white is certainly a shark that warrants a tremendous amount of respect. But there -- there is not a great population of great whites. And you really have to be in such a particular situation to have an issue with great whites.

MORGAN: The statistics on shark attacks in America -- I mean, they're not that alarming. The chance of being killed by a shark is one in 264 million. In the past decade, there have been 11 fatalities in the US. I was surprised at how low that was, actually.

Why is that? Why are there not more attacks, given there must be a lot of sharks in American waters.

CORWIN: Well, what's amazing is, for example, if you're off the coast of Florida and you're -- you are in the water, you're probably no less than 100 feet away from a shark. Sharks are around us. There are hundreds and hundreds of species of sharks, nearly 400. And only a handful of those are ones that could potential be dangerous to human beings.

But sharks really are designed to -- to target the prey that is a part of their environment. And human beings really aren't a part of their environment.

So there is some specific things we can do in our lives, in the environment of sharks, to avoid a problem.

MORGAN: What is the biggest misconception about sharks, do you think?

CORWIN: I think the biggest misconception is that they are just a -- a hardwired eating machine. I think sharks are -- are just --

MORGAN: I mean -- I mean, look, no disrespect --

CORWIN: Right.

(CROSSTALK)

MORGAN: -- your attempts to try and dilute that, but this bull shark's jaw here, I mean, I'm just feeling the teeth -- these are --

CORWIN: He could break your skin right now.

MORGAN: -- absolutely razor sharp.

CORWIN: We could be --

MORGAN: Yes.

CORWIN: -- we could be seeing the CNN medic if you --

MORGAN: (INAUDIBLE) off my hand.

CORWIN: -- just raked your hand there.

MORGAN: It would -- really, it would cut me open?

CORWIN: Right. And you can also see that behind it, you can see that -- just that incredible -- that sort of like crown of thorns --

MORGAN: Yes.

CORWIN: -- of teeth as they -- as they emerge up.

MORGAN: I've made a little list here of well known shark myths. I want to get some yes or no answers, or true or false.

Sharks are man-eaters. Are they naturally man-eaters?

CORWIN: Myth. Very -- very few sharks will target a human being. You have to be in the right situation -- dark water, murky water, a lot of chaos in that aquatic environment, maybe the breeding season and --

MORGAN: Would they eat human flesh? Do they like it?

CORWIN: Well, I think, like any predator, they'll take advantage of easy prey. And the sharks that we think of that would potentially target a mammal is the great white shark, and lots of time when that happens, it's the result of mistaken identity.

And there are examples of -- for example, a test bite, where a shark will come up and take a test and realize, you know, this is something --

MORGAN: They're not that keen on --

CORWIN: (INAUDIBLE).

MORGAN: -- on human flesh?

CORWIN: No.

(LAUGHTER)

MORGAN: Sharks will sink when they stop swimming. Is that true?

CORWIN: Some shark species actually can sink when they stop swimming. They don't have a traditional bladder like -- like your regular fishes do. Instead, they rely on their liver and -- and -- and other parts of their body for buoyancy. So they can sink.

MORGAN: Sharks have no bones?

CORWIN: They have no bones. They're --

MORGAN: Literally no bones?

CORWIN: They're made out of cartilage, which is -- which is what they share in common with the skates and the stingrays. They all belong to that group of animals without bones. Very ancient, ancient groups of fishes.

MORGAN: Sharks cannot live in fresh water.

CORWIN: That's not true. This shark right here --

MORGAN: The bull shark.

CORWIN: -- can actually venture into fresh water for weeks, if not months. And, in fact, there are landlocked sharks in parts of Central America that actually survive and thrive in those lakes.

MORGAN: All sharks can smell blood in the water from miles away.

Is that true?

CORWIN: I don't know if that's true. Clearly, they have an incredibly heightened sense of smell and taste and -- and, really, an amazing way to connect with the electromagnetic radiations and movements in the water. And they can pick out blood from a considerable distance. But it really would depend on which species of shark.

For example, is that a shark that would be connected to something that even produces blood like we do?

We have sharks like this species right here. This is primarily a -- a mollusk eater. This is eating clams and oysters and creatures of that type.

MORGAN: (INAUDIBLE) the -- the movie scenes when there's a sort of -- a lot of blood in the water and then you see a -- or a shark descending on them, is that, in reality, how it works? CORWIN: You can get a frenzy. You can get a feeding frenzy and there are -- there are accounts of people that have been shipwrecked -- we know that from World War II, when a -- when war vessels were sunk, people were preyed on sharks.

But, so, yes, in some situations, you need to protect yourself. But the truth is, there are things we can do in our lives to avoid sharks.

MORGAN: Yes.

CORWIN: As I said before, sharks are in so much more trouble than we are.

MORGAN: Do sharks eat each other?

CORWIN: Sharks actually can display some types of cannibalism. And what's really incredible to me is that some sharks will actually begin to eat each other -- eating each other in the womb. So you have --

MORGAN: Really?

CORWIN: Yes. So you have like great white sharks, or even like this species of shark right here. This is --

MORGAN: We've got a mini shark here.

What is this one?

CORWIN: This right here, this is a spiny dog fish, or a spiny shark. This is a shark that you can see right here along the coasts of New York. This is a shark that can grow upwards to five feet in length.

And when this animal was born, I don't think people realized this, but this is a creature that actually began its life in its mother, not as a free-formed egg that was laid in the nest. It actually was attached to a yolk sac and the mother gave birth to it. And she had maybe four or five.

And as I said with the great white sharks, these animals can have a number of babies in them and they'll actually -- when they come into the world, after many months of this pregnancy, they'll come out with the battle scars. And some sharks will never even get a chance to get out. They're actually eaten in utero.

MORGAN: But that -- that's off the coast of New York here. And that can grow to five feet --

CORWIN: Potentially five feet.

MORGAN: How dangerous would that shark be?

CORWIN: This is one of the least dangerous species of sharks. It's a shark that loves the cold water. And this is a shark that's actually a part of an incredible research project with the University of New England in Maine.

And what you'll notice is that this shark actually has a pit tag on it that basically serves as a -- as a way that this shark can always be identified.

And, you know, this is not a shark we need to worry about. In fact, this is a shark that needs management, because in some parts of the world, in places like Europe and the coasts of Spain, this is a species that some scientists worry could be eaten to extinction if they're not managed properly.

This is your fish and chips. If you go to England and you order fish --

MORGAN: All right.

CORWIN: -- and you hear of rock salmon?

MORGAN: Yes.

CORWIN: This is rock salmon right here.

MORGAN: All right.

CORWIN: Yes.

MORGAN: It's quite tasty, actually.

CORWIN: Don't tell him that.

(LAUGHTER)

MORGAN: What is the fish you least want to be if there are sharks around? What's their favorite eating fish?

CORWIN: Well, I guess it depends the species of sharks. But if I was a tiger shark, I don't know if I'd want to be a sea turtle off the coast of Hawaii. A tiger shark has a mouth this big. It can grab on, you know, to that maelstrom of shell and just shred that -- shell like shredded wheat.

I wouldn't want to be a -- a fur seal off the coast of South Africa during the feeding times for gore -- great whites or, with this species, this right here, very -- actually, this guy right here, a very famous shark. This is a shark that has a bad reputation, but it's totally not deserved.

This is the mako, a distant relative of the great white. But this is primarily a fish eater. And this, around here, it would be eating bluefish.

MORGAN: It's amazing array of -- look at them. And these are razor sharp.

CORWIN: Razor sharp. Absolutely incredible.

MORGAN: Incredible.

Let's take a break.

And let's come back and talk a little bit more about sharks, because everyone is quietly fascinated with them, aren't they?

CORWIN: Absolutely.

(COMMERCIAL BREAK)

(BEGIN VIDEO CLIP)

CORWIN: Sharks are fantastic creatures. And in truth, we've only just begun to understand them and uncover their many secrets. One thing we know for certain is that sharks are important and ancient members of the great ocean and that they deserve our respect.

(END VIDEO CLIP)

MORGAN: It's terrifying when you see them in the water. But sharks are also one of the most misunderstood creatures in the sea.

Back with me now is my special guest, Jeff Corwin, host of ABC's "Ocean Mysteries."

The sharks have been around 400 million years. What is the point of them? Why do we need sharks?

CORWIN: Well, it's sort of an interesting question. And it's certainly not the way a scientist would look at that question. We don't look at as a point to anything being here. You're here because you've made it through the evolutionary pathway.

But I think sharks do have a purpose. They are the apex predator. They're the number one dog in the food chain. And when we see them disappear, they -- I guess, in a way, Piers, they become like the canary in the coal mine that tell us that we are not taking care of our oceans correctly. When we go to an ecosystem that historically had sharks and those sharks have vanished, there's something wrong.

MORGAN: Does climate change have any impact on the sharks' population?

CORWIN: Climate change certainly can have an impact on the populations of some species of sharks. They are highly sensitive creatures. This shark species right here that we're looking at, this spiny dog fish needs cold, clean waters. And it isn't impossible that a species like that, with great fluctuations in change, could find an impact on its survival.

MORGAN: Is the biggest threat to sharks and their future, as with so many animals, human?

CORWIN: Absolutely. Human beings are driving many shark species, species that have been twisted and -- have sort of snaked away on this evolutionary journey for hundreds of millions of years, human beings, in short order, are driving many species to the brink of extinction.

MORGAN: When a shark attacks you, if you -- if you really, your luck is out and you're attacked by a -- a bull shark or a tiger shark, what is their technique?

What do they do to you?

CORWIN: Well, it -- again, depending on the species of shark. What a bull shark would basically do is the attack begins long before the bite happens. He's moving through that water. He's trying to sense any changes in this environment that he's just so highly plugged into.

And then he might cruise by. And then when he senses that moment of vulnerability, he's going to go for the greatest extension. And basically he's going to take these actually just --

(CROSSTALK)

CORWIN: Yes. And, so, basically, he's going to grab on with those sharp teeth and with that --

MORGAN: But where would he grab a human --

CORWIN: He could maybe by the leg, by the torso, by the front of the arm.

MORGAN: And does he -- does he clamp or rip?

CORWIN: He'll hold very tightly. We're talking hundreds and hundreds of pounds of pressure per inch of jaw. He'll clamp down tightly and he'll begin to shake. And literally, this will function like a chainsaw and saw through that flesh.

And what's really amazing about sharks is that even some of the smallest predatory sharks, when they bite, will typically take in about five pounds of flesh.

So, if you're on the bad end of -- if you're at the business end of a bull shark, you've got some troubles on your hand.

MORGAN: We've got a picture, actually, of somebody, I think on a -- yes, I mean --

CORWIN: But see now, you could see how a shark, a great white shark, could look up and mistaken that surfer as a -- as a seal.

MORGAN: Right.

CORWIN: But the truth is, this happens all the time. I was just filming in Hawaii for "Ocean Mysteries" and I started panicking, looking in my balcony, looking at all these people below and what none of them -- these thousands of people on the beach in Honolulu, what they don't see is this 12-foot long tiger shark going back and forth in between their knees.

MORGAN: And you could see it?

CORWIN: You could see it. And this shark had no interest.

How many times are people off the coast of South Africa, California, surfing away and never have a negative encounter?

Because this animal knows what it's targeting and rarely does it included people.

MORGAN: Have you ever been scared?

CORWIN: By a shark?

MORGAN: Yes.

CORWIN: I have been scared by a shark. We just finished this book called "Sharks" on this series we did. And, we gathered in a tremendous footage from a -- us working with sharks over the years. And I remember being off South Africa filming a great white shark. And I had this giant tank on my head that allowed me to talk and breath and communicate with the camera.

And I had too much CO2 so I was losing my ability to breath. And as they were trying to pull me out, a great white came up on the transom.

And so as I'm getting pulled out, there's a great white reacting to the electrical field of the -- of the engine motor. But still, you have to remind yourself that's one bloody powerful shark.

MORGAN: What animal does the shark fear in the water, anything?

CORWIN: I think probably there are a number of creatures. There are other sharks that prey on sharks. There are large mammals like dolphins, marine mammals or whales or killer whales.

MORGAN: A shark would be scared of a dolphin?

CORWIN: Absolutely. Yes.

MORGAN: Why?

CORWIN: They're incredible -- they have amazing defenses when a -- when dolphins feel threatened by sharks, they will plow at, you know, at torpedo speed into the side of that shark and actually --

MORGAN: Really?

CORWIN: -- kill. Yes, absolutely.

MORGAN: But a bull shark surely isn't scared of anything.

CORWIN: I have -- I have seen bull sharks that have -- have been at the wrong end of a fisticuff with a dolphin. Yes, dolphins are --

MORGAN: A dolphin has beaten up -- CORWIN: Yes.

MORGAN: -- a bull shark?

CORWIN: And orcas, killer whales have been known to take on sharks. These are highly intelligent, social marine mammals and they will send out -- you know, when they've got young, vulnerable animals, little babies, they will have this, you know, the sentinels there to defend that pod of animals.

(CROSSTALK)

MORGAN: Is a great white scared of anything?

CORWIN: I think a great white may be afraid of other great whites. And I think --

MORGAN: Do they fight each other?

CORWIN: They have been known to fight each other. I have seen young male great whites, like a nine -- females tend to be larger than the males. And I've seen males -- very amorous males -- walk away missing half their fin from, you know, a -- a female who wasn't feeling very sexy.

MORGAN: Fascinating stuff about sharks.

Let's take a break. When we come back, we've dealt with Jaws. Now I want to ask Jeff to take on the stingray. Let's get the sting out of the stingray.

(COMMERCIAL BREAK)

MORGAN: A relative of the shark family and most people don't think of stingrays as dangerous. And that may be an even bigger threat.

Back with me now is Jeff Corwin, host of ABC's "Ocean Mysteries."

So, this is a stingray tail?

CORWIN: Absolutely.

MORGAN: This is pretty big and --

CORWIN: This is from a -- yes, this is from a rough-tailed --

MORGAN: Pretty sharp.

CORWIN: -- stingray. And -- and you could imagine this --

MORGAN: Yes.

CORWIN: -- hitting you at, you know, at 10, 15 miles per hour. That could do some serious damage.

MORGAN: And this is where the sting comes?

CORWIN: That is the weapon of death. This is the tool that this creature uses, the stingray -- again, close call -- cousins of the sharks. This is -- it is this barb that penetrates the flesh of that would-be predator.

MORGAN: Right.

CORWIN: And it can deliver a -- a pain like an unimaginable level of pain. I've been stung by a stingray in my ankle and I can honestly say --

MORGAN: OK, talk me through what happened.

CORWIN: It was -- we were filming down there and I was walking in the shallows and I felt this electrical bolt, lightning bolt of pain in my ankle. And I thought it was a sea snake. And I remember the -- our guide there said to me, he said, you know, in Spanish, he said, you know, it hurts now, but I guarantee you, by tomorrow, as you go through this great journey of pain from this stingray, you'll be crying.

And sure enough, the next day, literally I was weeping in my bed with a doctor from San Jose doing surgery and -- and snipping my daughter's little teddy bear as -- as a -- for comfort and consoling.

MORGAN: And how big do they get, a stingray?

CORWIN: Huge. I mean, we're talking -- this stingray right here, so this is the tail.

MORGAN: Yes.

CORWIN: You would have to imagine a stingray --

MORGAN: Huge.

CORWIN: -- that could quite easily be the size of this table, weighing hundreds and hundreds of pounds.

For our TV series, the Georgia Aquarium is our partner and there, we have some stingrays that weigh thousands of pounds.

MORGAN: Would they actively go after a human being to --

CORWIN: Never.

MORGAN: -- to sting them?

CORWIN: No. It's -- it's totally by accident.

MORGAN: It's a defensive mechanism?

CORWIN: It's a totally defensive mechanism. They're -- I can't think of a creature least aggressive than skates and stingrays. You literally have to be very aggressive yourself to find yourself being poked by one of these --

MORGAN: Could you die of a stingray sting?

CORWIN: Oh, absolutely. Absolutely. This -- if this were to -- it's covered with bacteria. There are toxins that come from a sheath. It produces venom. We know, unfortunately, that people have died from --

MORGAN: In fact, Steve Irwin, the great crocodile hunter --

CORWIN: Absolutely.

MORGAN: -- he himself was pierced by a stingray.

CORWIN: Yes.

MORGAN: And it did -- it did take his life.

CORWIN: Absolutely.

MORGAN: So I mean there are -- there are cases like that.

CORWIN: It is. But you have to be in that situation close to that animal. That animal has to be startled in such a way that it would react. And in that moment of reacting, like trying to swim away, it makes contact with you, feels threatened in part.

I mean the only way this works is if it arches its tail when you come onto it.

So it really is a -- it is a last ditch effort defense.

MORGAN: Why are they sometimes called witches purse?

CORWIN: Well, the -- what the -- the reason why they're called witch's purses is actually because of this. This is the witch's purse. This is the egg of a skate that we find off New England. In fact, we have this female skate right here.

MORGAN: And we've got the engine running, because I think you've got a rather bigger --

CORWIN: Well, she --

MORGAN: -- creature in there.

CORWIN: -- she's consuming a lot of oxygen right there, so we keep this cold and oxygenated. So you can see her right here.

MORGAN: And a skate is like a mini stingray without the stick?

CORWIN: Exactly. You don't have a stinger there. And they can get large, but instead, what it has is very sharp little spikes and thorns on the tip of its tail. And this animal -- again, this is from the University of New England, from my colleague, James Sulikowski. And he works with these animals. And you can see, it is just so used to people.

But basically, this is the egg. And, actually, Piers, what's really cool -- I thought we were going to have something exciting. We thought this was going to hatch on television.

But it hatched a half an hour before you came. And this is actually a --

MORGAN: It's a little baby, isn't it?

CORWIN: This is a little baby that hatched out. She's brand new to the world.

MORGAN: A baby skate.

CORWIN: And you can actually see the yolk sac right there.

MORGAN: Yes.

CORWIN: That's been keeping her alive. And these animals have -- like sharks, these skates have such a very complex life history --

MORGAN: Is that the mother there?

CORWIN: This is the mother of these babies.

MORGAN: Right.

CORWIN: And this one is maybe a year old, this skate. Now that -- these guys are so used to people, they'll just literally come into your hand like that.

This skate is about --

MORGAN: The skate -- skates aren't dangerous, right?

CORWIN: They are not dangerous. But again, this is an animal we need to manage.

See, unlike fish, that can reproduce their whole life cycle in a year, this is an animal that, in some cases, with some -- some species of sharks and skates, they can't start reproducing until they're 20 years old.

And this egg, it didn't hatch out in a month or two. It could take two years for this to hatch out. In fact, right here, if you look -- and what I want you to do is if you hold this -- not like that!

(LAUGHTER)

CORWIN: So, if you hold that and you look --

MORGAN: Yes.

CORWIN: You can see -- MORGAN: That looks like an embryo.

CORWIN: There's an embryo in there.

MORGAN: That's amazing.

CORWIN: And you can see the eyes.

MORGAN: Yes.

CORWIN: And she is just -- this little --

MORGAN: And how long could that take to hatch?

CORWIN: This could -- if the water was warm, it could be in less than a year. In some cases, if the water is cold, it could be longer than a year.

This shark that we just looked at, that shark had spent up to two years inside his mother before it gave birth.

MORGAN: That's amazing.

CORWIN: So you can see that if this gets eaten or she gets eaten when she's very young, you've got a long journey ahead before this creature can replace itself.

And that's the big challenge we face, Piers, when it comes to managing and protecting these creatures.

MORGAN: Let's take a break.

Let's talk alligators when we come back. You're going to bring out a whopping alligator. A little bit bigger --

CORWIN: I am.

MORGAN: -- than these baby sharks you've had. This is where my nerves start to fray.

CORWIN: The dreams are coming true.

(LAUGHTER)

(COMMERCIAL BREAK)

(BEGIN VIDEO CLIP)

CORWIN: This 500-pound reptilian beast is a few feet from Tim's head and a little too close for comfort.

UNIDENTIFIED MALE: There you go.

UNIDENTIFIED MALE: All right.

UNIDENTIFIED MALE: All right. (END VIDEO CLIP)

MORGAN: One of the most feared reptiles in America, alligators are predators with a reputation for eating anything and everything, which is why Jeff Corwin, host of ABC's "Ocean Mysteries," is about to bring one out and stick it on the desk in front of me.

CORWIN: In just a few minutes, he'll be just a few inches from your head.

MORGAN: How big is it -- how big is this alligator?

CORWIN: Well, he's pretty big. But before we do that, I wanted to bring you a little teaser here, which we're taking part of your therapy, it would work you up.

(LAUGHTER)

CORWIN: This is a big guy.

MORGAN: So he's a baby alligator.

CORWIN: And you can just hold onto him very gently.

MORGAN: Right.

CORWIN: With both hands.

MORGAN: Um-hmm.

CORWIN: Both hands.

MORGAN: Um-hmm.

CORWIN: There you go. So these are young alligators. They're under a year in age. And basically, as these animals grow, they become very, very large.

But for me, what's amazing about alligators is they are one of our country's greatest conservation success stories.

This is a species that was pushed to the near brink of extinction, now has recovered to become one of the most iconic predators living --

MORGAN: And how did that happen?

CORWIN: They were over hunted. They dead -- dealt with habitat loss and also the pet trade drove these animals to extinction. It wasn't until the Endangered Species Act that they were able to recover.

Now, the threat that all crocodilians face today is climate change, because their eggs, how they hatch out, whether they are male or female, is determined by temperature, depending on the species.

So as our Earth warms up, we are getting unusual skews of males versus females.

CORWIN: All right. So we're going to do a little trade-off here. I've got him, you've got these guys.

(CROSSTALK)

CORWIN: Let's get this guy.

UNIDENTIFIED FEMALE: Watch his --

MORGAN: Don't drop him.

CORWIN: I just need you to hold him --

(CROSSTALK)

MORGAN: No, no, no, no, no, no.

CORWIN: So this right here.

MORGAN: You're in charge now.

CORWIN: This is a Nile crocodile. And this is the greatest river predator in all of Africa, a creature that could grow easily 50, 60 feet in length.

MORGAN: How old is this?

CORWIN: And this is probably a couple of years old. It was actually found walking down the streets of New Jersey.

MORGAN: Seriously?

CORWIN: Yes. This is -- was an animal that was rescued with someone --

MORGAN: How did it get there?

CORWIN: It was an illegal pet. And they just got tired of it and let it go.

And you can see, one of the big differences, you can see the way the jaw is structured, very different from alligators.

So --

(CROSSTALK)

MORGAN: But did it truly live in New York subways? Is that a myth?

CORWIN: It is not true. They do not live there. These animals are creatures that are tropical or subtropical and they could not survive an unforgiving New York winter.

MORGAN: But even at that size, is it dangerous? CORWIN: It's not dangerous, but it certainly could hurt you.

MORGAN: Hmmm.

CORWIN: If he bit you, it would really hurt. But he probably wouldn't --

(CROSSTALK)

CORWIN: I've done -- I've done stories with people that have been eaten by crocodiles.

MORGAN: If that's the crocodile, the previous little ones were alligators, I can't really tell the difference. What is it?

CORWIN: You can tell the way the -- the -- the snout is shaped. The -- the gators and Caymans have a more rounder snout. You can see the way the teeth line up completely different on a crocodilian, the way they are -- eyes are, the way the tails are. There's well over 20 different species of crocodilians --

MORGAN: Who's more dangerous, crocodiles or alligators?

CORWIN: I would -- to me, they're -- I will swim in alligator country if I feel the risks are low. You'll never see me swimming in the Nile River.

MORGAN: Why?

CORWIN: Because I think you'd risk a chance of be being, you know, the early buffet of a -- of a crocodile --

MORGAN: But these things --

CORWIN: -- before the wildebeest comes.

MORGAN: -- are the most dangerous of the reptiles, huh?

CORWIN: I think they're remarkable predators. But speaking of predators, we'll take this guy back.

MORGAN: Um-hmm.

CORWIN: And we're going to bring out --

MORGAN: The big boy.

CORWIN: -- the big boy.

MORGAN: OK.

CORWIN: This alligator has an incredible temperament, which is very unusual.

MORGAN: Does he have a name? Let's personalize it.

CORWIN: I think it's Fred, right?

UNIDENTIFIED FEMALE: Yes.

CORWIN: It's Fred the alligator. Fred was found living in a pond in New England and was rescued. He was someone's illegal pet. And that's why --

MORGAN: How many people are keeping these things as pets?

CORWIN: A lot of people, believe it or not, keep them as pets. And they don't make good pets. They belong in the wild --

MORGAN: No kidding, Sherlock.

CORWIN: But --

(LAUGHTER)

CORWIN: -- but these animals, they really are -- they're what we call a keystone species. The environments where they live, they are critical to keeping those environments healthy. They are often called landscape architects, because when a gate -- a bit gator like this moves through the water, he's creating an open waterway.

MORGAN: He's magnificent. But he -- he looks kind of dinosaur- like.

CORWIN: They do have a prehistoric look. And they have been on this Earth for a long time. Crocodilians have been on this planet for 60 million years.

But whenever you see something alive today like that Nile croc or an American alligator, it is a very modern animal that has evolved to take in the challenges of our world today.

MORGAN: How long can they live?

CORWIN: Well, that's kind of a mystery. We don't know that. We know that they continue to grow throughout their lifetimes. Something neat about sharks and crocodilians is they have an exquisite amazing resistance to disease. When they're younger, they grow faster. And as they get bigger and older, they start to slow down.

But this animal could live for many, many years, easily as long as a human being.

MORGAN: I mean he looks, Fred, very docile. But they all look a bit docile until they kill you, right?

CORWIN: Yes. He probably -- if he has one bad day, you're going to need your belt for a tourniquet.

MORGAN: What would he do?

CORWIN: Well, if he was in predator mode, basically, what he would be doing is just sort of hunkered down like a submarine low to the water. And basically most of his head would be covered.

And as you see, Piers, he's got this incredible camouflage that allows him to melt into that watery world.

And, in fact, he even has his own version of like a snorkel as mask. If I close his eyes -- if you guys zoom in tight to the eye. Watch as we open it up.

You can see that lens come across.

Do you see that?

MORGAN: Wow! Yes.

CORWIN: That's called the nictitating membrane and that allows him to protect his eyes. You keep them open. But when he comes in, he uses those powerful jaws to grab onto his prey. It could be a turtle. It could be a large-mouth bass.

MORGAN: And the bull -- the bull shark, you said, basically (INAUDIBLE).

CORWIN: He'll grab on and shake and --

(CROSSTALK)

MORGAN: What will this do for you?

CORWIN: He will basically hold on very, very tight. He'll take that white-tailed deer, pull it down to a watery grave. And once that animal has expired, he'll begin to rip it apart.

MORGAN: So they drown you first?

CORWIN: Oftentimes, they will drown you, if they don't crush you first, depending on your size. And then they'll twist and roll. And as they twist and roll, segments of that animal being killed just tear away.

MORGAN: Why are you so calm around something that could, at any moment, turn predatory?

CORWIN: Well, you know --

MORGAN: I presume they can.

CORWIN: -- I'm playing the lottery, in a way. But I know --

MORGAN: Yes, but you're playing it with me at the moment.

CORWIN: Yes. But if you notice, I do keep a safe distance. I'm keeping back. I know Fred has a good temperament, but I don't want to be there when he has that one bad day.

(CROSSTALK)

CORWIN: And that's something we need to remember about all these animals. They are powerful predators built for surviving.

MORGAN: Let's take a break. And no disrespect, Fred, I'd like to see the back of you quite quickly.

When we come back, survived sharks, stingrays, and now alligators. All that's left is the one thing that we all hate, really, snakes. And there's a massive, gigantic python heading my way.

(COMMERCIAL BREAK)

MORGAN: Just when I thought this hour couldn't get any more unnerving, a large Burmese python is about to appear. I've got a feeling someone is trying to tell me something here.

But I'm back now with wildlife biologist, Jeff Corwin.

So, Jeff, in that box --

CORWIN: Yes.

MORGAN: It's a little bit like when they brought Hannibal Lecter out of his cage.

What have you got in there?

CORWIN: All your nightmares are coming true.

MORGAN: All your boxes contain horror stories.

CORWIN: So this, my friend -- oh, my goodness --

MORGAN: Oh, my God.

CORWIN: -- is one of the largest snakes in captivity.

MORGAN: Wow!

CORWIN: This is a -- a Venus neck popping python.

MORGAN: No kidding.

CORWIN: My chiropractor is going to love this.

MORGAN: How big is that?

CORWIN: I'd ask for help, but I know I won't get it.

MORGAN: No, no, no, no, no. You just -- you just --

(CROSSTALK)

CORWIN: Let me guess, Piers. You're the first one in the life boat, right?

All right. (LAUGHTER)

CORWIN: Where are you going?

So this, Piers --

MORGAN: How big is it?

CORWIN: This -- he's 15 feet long.

MORGAN: Jesus.

CORWIN: He weighs --

MORGAN: Whoa.

CORWIN: -- nearly a couple of hundred pounds. And this is a Burmese python.

MORGAN: It's massive. I'll keep the head (INAUDIBLE) --

CORWIN: This, of course, is an animal that started out as an illegal pet. It was confiscated and it is now a part of this educational program.

MORGAN: Where do people get these from a pet?

CORWIN: You can buy them in pet shops. You can get them online. And now, many, many states are passing laws prohibiting you from having them as pets.

And, of course, these animals, in their element, Piers, where they live, in the jungles of Southeast Asia, perform an incredible purpose.

But in the Everglades of Florida and the American South, this is an invasive species that's eating our native wildlife to extinction.

MORGAN: What do they do in the jungle that's so positive?

CORWIN: Well, they're a part of that living community. They're part of the ecosystem. When a big female snake like this, she'll produce 50, 60 eggs. They are consumed by other animals.

When you begin your life as a Burmese python, you ain't this big. You've got to work your way up. And the odds --

MORGAN: How --

CORWIN: -- are against you --

MORGAN: -- how old is this one?

CORWIN: This animal is probably five or six years old.

MORGAN: Does she have a name? CORWIN: I think they named it Buddha. I did not name it Buddha, but I do believe that is her name. And, she's still growing. She could maybe reach 20, 25 feet in length and have a growth of near telephone poll size.

MORGAN: What did the python do to -- does it constrict you? Is it as simple as that?

CORWIN: It literally squeezes the life out of you. For this animal to begin the hunt, the first thing it will do, it will tickle out that forked tongue. It's picking up those molecules in the air. He actually has, almost like a reptile computer. It's called the Jacobsen organ.

And it's in his mouth and he's able to determine whether you're a potential mate or you're potential prey. And once he determines you're prey, let's say you're a small little rainforest antelope or monkey, he'll reach out with razor sharp teeth, latch on and then coil around you.

And basically, he's got incredibly strong muscles.

Let me show you something that's neat. If you watch my finger -- just to show you how sensitive those muscles are -- they will actually form around my finger --

MORGAN: Yes.

CORWIN: -- as it sort of -- as they sort of give --

MORGAN: They're very, very powerful.

CORWIN: Very. And it's these muscles here that are powerful. So basically, those lateral --

MORGAN: So they've --

(CROSSTALK)

CORWIN: They -- it's not really choking. They get tighter as you exhale.

MORGAN: Do -- could they kill a human?

CORWIN: It is very possible that a large snake could kill a human. It is not their natural prey. The people have been --

MORGAN: Why are you so comfortable around it?

CORWIN: Because I know -- I -- I know his behavior. Snakes are, you know, I've spent my life studying snakes. I did my graduate work on snakes.

So I can tell, if this guy was upset and this animal was being aggressive, we would not be so cavalier with this animal.

MORGAN: What would it do to show that it's stressed?

CORWIN: Well, it would be coil up. It would be hissing, making a lot of disturbing behavior from hissing and noise. And then it would be striking.

And when you get -- when you get struck by a snake like this, it has hundreds and hundreds of very sharp glass-like shards of teeth in its mouth. And it can do a lot of damage.

MORGAN: It's an extraordinary animal.

CORWIN: Amazing, especially to think that this is a creature that survives without legs, without ears, even without eyelids. But yet it -- it's perfect.

But something that's interesting about snakes, like, you go at the back end of this just colossal serpent -- I don't know where he's going to go, but I'll hold onto this end.

So if I were to ask you, do snakes have legs, what would you say?

MORGAN: I would say they don't.

CORWIN: They don't. But if you look at my finger, you can also see a claw.

MORGAN: Right.

CORWIN: And what you're looking at is the evolutionary story of how snakes began. The ancestors of snakes, if you look right there, where my finger is, right there, that is a vestigial claw that tells us that it's likely they evolved from creatures that had legs, a lizard-type animal, probably like a monitor lizard.

MORGAN: What is the biggest creature this kind of python could eat, who is in -- in the jungle?

CORWIN: Well, you know, in the Amazon, the Anaconda, which is a large boa. They can, they sometimes call them bull killers.

These animals have been known to eat small livestock. They have been known to eat, uh, other crocodilians and other reptiles.

So this animal can basically fit something about seven times bigger than its head in its mouth.

MORGAN: So if we put Fred and Buddha together on the table --

CORWIN: I -- I --

MORGAN: -- who would win?

CORWIN: I don't think -- these animals -- who would win?

Nah, I don't really --

(CROSSTALK)

MORGAN: -- had a fight, who would win?

CORWIN: It depends who grabs on first and where, you know?

If a pred -- let's say this guy was in the Southeast Asian jungle and a crocodilian came onto it and grabbed onto it, grabbed it by the head, that would be a dead snake. But if the snake snuck up and takes (ph) his way to that crocodile, latched on, twisted around it, you'd have a dead crocodilian.

I mean they are just incredible predators.

MORGAN: Amazing. It's an amazing animal.

MORGAN: Well, Buddha, it's been a delight, but I'm going to have to say good-bye to you, too, unfortunately. And we're going to bring out the largest toad in captivity.

(COMMERCIAL BREAK)

(BEGIN VIDEOTAPE)

DR. GEORGES BWELLE, CNN HERO: For a country like mine, people like to drink, to dance, to enjoy their life. But with poverty, they cannot enjoy their life.

To go to the village is a pleasure. If I can help two or three people, that would be great.

I saw my father ill for 23 years. Before he passed away, he asked me -- you see how people suffer to see a doctor? Please, if you graduate to be a doctor, help people.

My name is George Bwelle. I bring free surgery and health services to the people of rural Africa.

They're beating the drums, says thanks to come. They can live 60 kilometers around and they are coming on foot.

We are starting by doing consultation. And in afternoon, we have a list of patients that we are going to operate.

We need our generator because in the village there is no light. We start doing operations until Sunday morning. And we are doing around 40 surgical operations for free.

UNIDENTIFIED MALE: I have no money, that's why they brought me here. This will change my future, in my family.

BWELLE: We leave our address to all the patients that if there's any problem they can come back to us.

I help people and they are happy.

I'm bringing that to give them opportunity to restart. (END VIDEOTAPE)

(COMMERCIAL BREAK)

MORGAN: Back with my special guest, Jeff Corwin.

So, Jeff, we got pythons, alligators, stingrays, now. we're going to end the show with one of the biggest toads in captivity.

CORWIN: Absolutely. He's ready for his own Jennie Craig moment.

(LAUGHTER)

CORWIN: The biggest -- he's ready to step on the scale. And when you think of toads --

MORGAN: Yes.

CORWIN: -- like here in the Northeast, we have the little American toad.

MORGAN: Um-hmm.

CORWIN: And sometimes you get toads like this.

MORGAN: Oh, my God. He's huge.

CORWIN: He's absolutely gigantic. This is the marine toad from South America. And it's an amphibian. And that's a group that includes the frogs and the salamanders and newts.

But around the world, we're losing our amphibians. We will likely lose half of all amphibians halfway through this century. And these are animals that have been on our planet for 350 million years.

And they're disappearing largely because of a deadly fungus called chytrid fungus. So there's a chance that this amazing amphibian could be extinct in the wild some day.

MORGAN: And this constant thing with its -- its -- what do you call it gut?

CORWIN: No, this -- that's his chin and this is called buccal pumping. And what he's doing is he's actually -- pumping that back and forth and he's drawing air into his nostrils. And he's got a very wet vascular membrane in his mouth and it's a way -- it's a way he can breath.

These animals not only use their lungs to breath, but they also breath through their skin. It's called cutaneous respiration.

And that's one of the biggest problems with them. The reason why amphibians around the world are in trouble today is because as they breathe through their skin, they can take toxins in their skin and they can be killed by this deadly fungus.

MORGAN: Of all the creatures that you've found in the ocean or seen, what's been the most amazing moment for you?

CORWIN: I think probably one of the most amazing moments for me was recently filming in New Zealand and actually coming face with a bird species that actually was extinct in the wild and they had rediscovered it. It was a type of kiwi called the haast kiwi. And this was for the "Ocean Mysteries" series.

And well, for me, being in Amazon jungle with the scientists and actually finding a species and rediscovering a link that could some day save that species.

MORGAN: Could -- couldn't the public around the world be doing a lot more to help conserve the great creatures of the ocean?

CORWIN: Absolutely, Piers. Ultimately, we're the ones that pay the price. That's why I do this TV series. That's why I wrote the book, to try to excite people and make them focus on being good stewards.

So I would ask you this, what do we lose when we lose amphibians? What do you think we would lose? That's my question. What do you think?

MORGAN: Nothing. I think they're -- I think they should all be preserved.

CORWIN: Yes. But a lot of people don't realize that we lose medicine. A lot of the medicines we use in our lives -- anesthesia, anti-fungal agents -- begin in an amphibian skin as a toxin. So the poison dart frog, we take that and turn it into a neurological anesthesia.

We lose keystone species and we lose the ultimate canary in the coal mine for the state of our planet's health. When these animals disappear, it tells us we've got some serious managing to do of our natural resources.

MORGAN: Well, Jeff, it's been a fascinating hour.

CORWIN: Thank you.

MORGAN: We've had it all. You do great work with these --

CORWIN: Thank you.

MORGAN: -- creatures and it's a great insight into how to operate.

"Ocean Mysteries" with Jeff Corwin airs on ABC stations nationwide. And the book is called "Sharks"?

CORWIN: "Sharks" is our new book. It's part of the Jeff's Explorer series. It's the first interactive trans media book on sharks.